Minimize the number of docker jobs

[carmocca]

What does this PR do?

We currently generate more Docker images than we use for testing. This PR changes that to reduce the number of possible failures.

This reduces it from 49 docker jobs to 16

Part of #10060

Does your PR introduce any breaking changes? If yes, please list them.

None

Before submitting

• Was this discussed/approved via a GitHub issue? (not for typos and docs)
• Did you read the contributor guideline, Pull Request section?
• Did you make sure your PR does only one thing, instead of bundling different changes together?
• [n/a] Did you make sure to update the documentation with your changes? (if necessary)
• [n/a] Did you write any new necessary tests? (not for typos and docs)
• [n/a] Did you verify new and existing tests pass locally with your changes?
• Did you list all the breaking changes introduced by this pull request?
• [n/a] Did you update the CHANGELOG? (not for typos, docs, test updates, or internal minor changes/refactorings)

PR review

• Is this pull request ready for review? (if not, please submit in draft mode)
• Check that all items from Before submitting are resolved
• Make sure the title is self-explanatory and the description concisely explains the PR
• Add labels and milestones (and optionally projects) to the PR so it can be classified

[codecov]

Codecov Report

Merging #10202 (4193f24) into master (5262b63) will increase coverage by 0%.
The diff coverage is n/a.

❗ Current head 4193f24 differs from pull request most recent head 3d490cd. Consider uploading reports for the commit 3d490cd to get more accurate results

@@           Coverage Diff           @@
##           master   #10202   +/-   ##
=======================================
  Coverage      89%      89%           
=======================================
  Files         180      180           
  Lines       16184    16146   -38     
=======================================
- Hits        14324    14317    -7     
+ Misses       1860     1829   -31     

[SeanNaren]

nice!

[tchaton]

LGMT!

[Borda]

We currently generate more Docker images than we use for testing. This PR changes that to reduce the number of possible failures.

how not testing shall help? if I read it correctly we just say we do not test some confirmation so if they do not work we do not care?
also, why are you keeping for updating docker images only py 3.6 which we do not use for testing?

[carmocca]

we do not test some confirmation so if they do not work we do not care?

This is already the case. Since these jobs are not required, they often fail and nobody cares (until there is a problem and CI gets blocked). This PR cuts the unused images, so we only keep those that are used for actual testing jobs later.

[daniellepintz]

Amazing, thank you!